The Black Esophagus.

Acute esophageal necrosis (AEN), commonly referred to as black esophagus, is a rare clinical condition resulting from a combination of ischemic insult and thromboembolic injury to the esophagus. It is characterized by the circumferential black appearance of the esophagus. The risk factors for the development of AEN include coronary artery disease (CAD), diabetes mellitus, hypertension, malignancy, and alcohol use disorder. The treatment is directed at correcting the underlying medical conditions, supportive measures, and gastric acid suppression. We present the case of a 60-year-old female with multiple medical comorbidities who was detected to have a black esophagus during the evaluation of anemia.

Gastrointestinal Hemorrhage From Esophageal Dissecans Superficialis After the Initiation of a Tyrosine Kinase Inhibitor.

Esophagitis dissecans superficialis (EDS) is described as the peeling of squamous mucosa of the esophagus with regurgitation of esophageal casts. It is a rare endoscopic finding associated with chemical irritants, autoimmune disorders, or medications. Most patients are asymptomatic but clinical manifestations can include dysphagia, heartburn, bleeding, or vomiting. In this report, we present a case of a 70-year-old man with a previous history of small cell lung and hepatocellular carcinoma for which he had undergone chemoradiation and immunotherapy. He had presented with upper gastrointestinal hemorrhage manifested as coffee ground emesis. Endoscopic findings were consistent with EDS. No recurrence of his gastrointestinal hemorrhage was observed after acid-suppressive therapy. With our case report, we aim to increase awareness for EDS as a differential diagnosis for gastrointestinal hemorrhage.

Tethered Swimming for the Evaluation and Prescription of Resistance Training in Young Swimmers.

The aims of the present study were 1) to evaluate the effects of 11 weeks of a typical free-swimming training program on aerobic and stroke parameters determined in tethered swimming (Study 1; n=13) and 2) to investigate the responses of tethered swimming efforts, in addition to free-swimming sessions, through 7 weeks of training (Study 2; n=21). In both studies, subjects performed a graded exercise test in tethered swimming (GET) to determine anaerobic threshold (AnT), stroke rate at AnT (SRAnT), peak force at GET (PFGET) and peak blood lactate ([La-]GET). Participants also swam 100-, 200- and 400-m lengths to evaluate performance. In Study 2, swimmers were divided into control (i. e., only free-swimming; GC [n=11]) and tethered swimming group (i. e., 50% of the main session; GTS [n=10]). The results of Study 1 demonstrate that AnT, PFGET, [La-]GET and 200-m performance were improved with free-swimming training. The SRAnT decreased with training. In Study 2, free-swimming performance and most of the graded exercise test parameters were not altered in either group. However, [La-]GET improved only for GTS. These results demonstrate that aerobic parameters obtained in tethered swimming can be used to evaluate free-swimming training responses, and the addition of tethered efforts during training routine improves the lactate production capacity of swimmers.

Mimicking PAMAM Dendrimers with Ampholytic, Hybrid Triazine Dendrimers: A Comparison of Dispersity and Stability.

Two strategies are applied to mimic the ampholytic nature of the surfaces of half-generation PAMAM dendrimers and yet retain the very narrow dispersity inherent of triazine dendrimers. Both strategies start with a monodisperse, single-chemical entity, generation two triazine dendrimer presenting twelve surface amines that is available at the kilogram scale. The first method relies on reaction with methyl bromoacetate. Complete conversion of the surface primary amines to tertiary amines occurs to provide 24 surface esters. Extended reaction times lead to quarternization of the amines while other unidentified species are also present. The resulting polyester can be quantitatively hydrolyzed using 4M aqueous HCl to yield a dendrimer with 12 tertiary amines and 24 carboxylic acids about a hydrophobic triazine core. The second method utilizes Michael additions of methyl acrylate to yield 24 surface esters. This reaction proceeds more rapidly and more cleanly than the former strategy. Hydrolysis of this material proceeds quantitatively using 4M aqueous HCl to yield desired dendrimer. In both cases, MALDI-TOF mass spectrometry provides compelling evidence of reaction progress. Electrophoretic analysis confirms the ampholytic nature of these materials with the former targets having a pI value in the 1.8 < pI < 3.4 range, and the latter having a pI value in the 4.7 < pI < 5.9. These ranges bookend the pH range within which PAMAM dendrimers become zwitterionic, 3.4 < pI < 4.7. The strategy of using monodisperse amine-terminated dendrimer constructs as core offers significant advantage over PAMAM homopolymers including dispersity, ease of characterization and batch-to-batch reproducibility. These triazine dendrimers could ultimately be adopted into materials with applications wherein the demands of purity have hitherto remained unsatisfied.